Subject: Re: uvm_fault
To: None <segv@netctl.net>
From: Thor Lancelot Simon <tls@rek.tjls.com>
List: tech-kern
Date: 01/29/2006 02:19:53
On Sat, Jan 28, 2006 at 01:58:53AM +0000, segv@netctl.net wrote:
> Hi, I have a script that sets up a chroot environment under /opt/sandbox by
> calling 'mount_null' to mount /bin, /sbin, /lib, /usr/bin, /usr/sbin, /usr/lib,
> etc under /opt/sandbox. When some of the directories are exported via NFS and I
> call this scripts on the server that exports those directories, I get a kernel
> panic. This is on a pretty recent NetBSD-current.
> 
> uvm_fault(0xcace89a0, 0, 0, 1) -> 0xe
> kernel: supervisor trap page fault, code = 0
> Stopped in pid 543.1 (mountd) at 0: invalid address

I've seen a huge number of these on multiprocessor machines -- you mention
in a later message that your system has two CPUs.  Our quad-CPU build
systems see them very frequently, while our dual-CPU systems see them
hardly at all.

It's been suggested that these are memory errors -- that is, hardware
failures -- but I can't see any other evidence that the memory in these
systems is bad.  I think we must have some kind of race in the VM system.

-- 
  Thor Lancelot Simon	                                     tls@rek.tjls.com

  "We cannot usually in social life pursue a single value or a single moral
   aim, untroubled by the need to compromise with others."      - H.L.A. Hart